# ADL5205 - Output Voltage Swing and Output Current

Dear ADI Support Team,

I would like to understand how did you measure the P1dB=+17dBm (exact freq point is not important)? There is confusion present, since the datasheet gives data for the chip itself and the eval board (S parameters) includes output 50R resistors on each output - am I right? So what was used for the P1dB measurement?

In addition, the figures for the output voltage swing of 5.4Vpp (4.5Vpp) defined at P1dB and the Zload=200Ohm and the short-circuit current do not match at all. Maybe I'm missing something here?

OK, let's see: 5.4Vpp on 200R equals 27mA, but the short circuit current is only 22mA. Please help...

Thank you and best regards,

Leon

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[edited by: Lpavl at 12:01 PM (GMT -4) on 2 Sep 2021]
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• HI Leon,

Based on the data sheet the P1dB is measured with a 200 Ohm load. The 17dBm into 200 Ohms is 9V peak to peak which means 45mA peak to peak. This means 22.5 mA peak which is not far off from the 22mA short circuit number.

Hope this helps.

Warm Regards,

Rachana

• Hi Rachana,

just one more thing, the Output Stage data in the datasheet states 5.4Vpp at P1dB @200MHz, 200R load. But at the following section Noise/Harmonic Performance, the P1dB is 17dBm, as you have correctly calculated that is 9Vpp. Why 5.4Vpp does not match 9Vpp?

Thanks again and best regards,

Leon

• Hi Leon,

In the test condition section for the output stage right above ‘At p1dB gain code=00000’ it says Vout+ and Vout-. I wonder if they are showing peak to peak voltage of each output rather than differentially. In that case you would expect it to be half of 9Vpp which is 4.5Vpp.

Hope that helps.

Warm Regards,

Rachana

Reply
• Hi Leon,

In the test condition section for the output stage right above ‘At p1dB gain code=00000’ it says Vout+ and Vout-. I wonder if they are showing peak to peak voltage of each output rather than differentially. In that case you would expect it to be half of 9Vpp which is 4.5Vpp.

Hope that helps.

Warm Regards,

Rachana

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